truckn

I bought a used 2004 Jeep Grand Cherokee Laredo "Freedom Edition", which has an eight cylinder engine. The tires are still in good shape, but I want to buy custom wheels. How do determine what wheel width, bolt pattern, and offset to select?

The current tires are P235/65R17, so I assume the current wheel diameter is 17. I have tried using a number of online wheel retailers, and there does not seem to be a set wheel width or offset for my Jeep year/model. Can't say I understand the bolt spacing measurement either.

Help?!

Fred/N0AZZ

Yes my 04 "Overland edition" came with P235/65R17 on it

truckn

Does that mean you have specs for the wheels you can post?

dave1123

It does get confusing, doesn't it?

Wheel diameter is the diameter of the tire mounting flange at it's bottom edge.

Rim width is the distance between the tire mounting lips on the inside.

Bolt pattern is the number of bolts and the circle diameter; as in a 5x5 is 5 bolts in a 5" circle, that's 2.5" in radius measured from the wheel center.

Offset is the distance the back of the mounting flange is off the center of the wheel width, either positive or negative.

Back spacing is the distance from the back side of the wheel to the mounting surface.

SO, a 17" wheel on your jeep is probably a 7, 7.5, or 8 inch width, 5x5 pattern, with an offset you'll have to measure.

truckn

I haven't looked at the spare yet, do these vehicles have full size wheels for the spare?

... thinking I could measure the wheel on the spare instead of having to take off a wheel from the vehicle.

GCWJ

That tire is for a 9" section width, (235/25.4). The rim is indeed 17.

(235*.65*2)/25.4 is about 13", plus the 17" rim you get a 30" tall wheel, nominally. Put weight on it and obviously it'll squish a bit

The 235 is the width of the cross section. The 65 is the aspect ratio of the section, which means that the sidewall to the tread is nominally 65% of the P width. The R, as you figured, is the rim diameter.

If you want taller tires, for instance, you can use the formula above to back- figure if a tire will fit. Essentially, take the diameter and subtract the rim:

31" (example) tire minus your 17" gives 14. 14/2 is 7, which is the height of your sidewall. What you need to do is find a P and ratio combination that gives a 9" width and a 7" sidewall height. So. Your width still needs to be 235 as that's roughly 9" per above. 7" in mm is about 178. 178/235 is .75.

Voila, a 31" diameter, 9" wide tire on a 17" rim will be a P235/75R17.

Widths in real life fluctuate. 9.25" wide is a 9" wide tire. I say "nominal" because real life and math on paper are often two different things! All this works using these numbers, but the section width is really at the widest point of the section. The rim itself is probably 8", but keeping the P value the same as what's on there will ensure that the new tire you buy will fit the rim you already have.

(If I screwed is up someone PLEASE do me a favor and correct me!)
(edited for bad math, bad brains, and the fact that I've been awake for about 15 hours already and it's only 7pm...!))

dave1123

You have to be careful measuring the spare. I say that because my 2000 WJ came with 245/70R16s on 7.5" wide rims, whereas my factory spare is a cheap-shot 17" tire on a 5.5" wheel! It is however, the same diameter as my 245s at 29.5". I had one tire from my last set that was still good because it was replaced on a road hazard guarentee so I thought I'd use it for my spare. I'd have to buy another rim to do that!

Most newer model jeeps seem to have tire clearance set up for a 30" tall tire MAXIMUM without suspension lifts, so they play games with rim diameter and profile. If you've got with more than a 245 width, you'll need wheel spacers or wheels with less backset.

GCWJ

Mine came with P225/75R16s, and luckily I bought the jeep used with a real spare that already had the same size tire on it. My wife's has that horrible donut. We ended up buying a set of 3 on CL for super cheap (this week!) so when we replace her tires this fall we'll do a set of 5 and hook her up with a real one also. I hate donuts.

What's the real plan for the custom wheels? Bigger, or prettier, or some combo? ​​​​​​​It's hard to say what the right plan of action is without knowing that, but Dave's right that a wider tire will require a rim with less back spacing in order to move the plane of the wheel away from your wells. Too much spacing will move the tire in and possibly cause it to rub on stuff. Wheel spacers can help but you've only got so much lug to space out on.

94zj318

The largest tire a WJ ever came with is P245/65R17 on 17"x7.5" rims with a 5x5 bolt pattern. Any rim from an '07-'17 JK Wrangler/Wrangler Unlimited, a '99-'04 WJ Grand Cherokee, an '06-'10 Commander, or even an '11-'17 WK2 Grand Cherokee should fit without a spacer, though you CAN add a spacer if you need to use a different bolt pattern.

On my '02 WJ Grand Cherokee, I'm running P225/75R16 Cooper Discoverer AT/3's with 16"x7" alloy rims (the first ones listed on this page: http://www.originalwheels.com/jeep-w...er2007rims.php). They actually look like they came stock on the WJ Grand Cherokee... the 16"x7" Silverblade alloys are a PAIN to keep clean, and mine were beginning to oxidize.

dave1123

Yes, according to my VIN, my 2000 WJ came factory equipped with 245/70R16 tires on Timberline 16x7" wheels. They are about the biggest tire that can fit and not rub the liners. They are 29.5" in diameter. I have Cooper Discoverer AT3s on it and I sometimes find that they rub briefly coming down a steep driveway in a sharp turn once hitting the street, but those are extreme conditions. I probably could use a 2" lift for snowpack clearance because my liners are toast at this point.

The difference between a 225 and 245 is only about 3/4" (20mm). The diameter of the 225/75s and the 245/70s are about the same.

SteveMongr

Following link has explanation of bolt pattern, offset, backspacing, etc. Also specs on all stock jeep wheels. http://www.morris4x4center.com/knowl...ifications.htm

94zj318

Yeah when I bought a set of 16"x7" Wrangler JK wheels for my Jeep (5 including an unused spare) they came mounted on P245/75R16 Goodyear Wrangler SRA's, but I ended up keeping my Cooper Discoverer AT3's and Goodyear Wrangler ST spare (both P225/75R16) due to the fact that they were nearly all new.

I don't find that my Coopers rub, but they ARE noisier due to the more aggressive tread on them.

The 2000 WJ's had two wheel options: either the 16"x7" Timberlines that came on all Laredos, or the 16"x7" Silverblade I's (the gold option was discontinued after 1999, I think) that came on the Limited, OR you could option them up with a Laredo, but only IF you ALSO optioned up the 26F/28F/2TF Packages... my neighbors had a Laredo 28F Package with the Silverblade I's, and I could never figure out why they didn't have the Timberlines until I got ahold of a 2000 Jeep Book.

GCWJ

I wish they'd fix that page layout so it worked with android browsers. Half the right side is cut off, and because the nav bar on the left comes back when you flip the phone, it's even worse sideways.

dave1123

For all the options and different model information on WJs, go to wjjeeps.com For later models, go to wkjeeps.com or wk2jeeps.com

Fred/N0AZZ

My WJ came with a full size spare mounted on a 17" chrome/aluminum polished spoke wheel, same as mounted ones on it.

If/when you change your size to anything other than stock a new speedometer gear is required just to make the computer happy with correct info.